Antenna



L. M. PERKKNS Jan. 16, 1934.

ANTENNA Filed May 31, 1930 Qwuentoz LAURENCE MPERKINS' Warm/Mala Patented Jan. 16, 1934 PATENT OFFICE ANTENNA Laurence M. Perkins, Dayton,

Ohio, minor, by

mesne assignments, to Radio Corporation of America, New York, Delaware N. Y., a corporation of Application May 31, 1930. Serial No. 457.727

3 Claims.

This invention relates to an antenna and more particularly to an antenna mounted on a motor vehicle.

Whenever radio receivers are mounted in motor vehicles provided with an electrical ignition system disturbances are picked up by the radio receiver that are caused by the arcing across the spark gap and to transient currents set up in the electrical system. For this reason, numerous precautions must be taken and methods used so as to avoid the interference of the disturbing signals.

In radio receivers ordinarily used, the antenna is usually placed the same height above ground, which cooperates usually with the surface of the ground in forming a condenser. When a radio receiver is mounted in a motor vehicle and especially in a motor vehicle provided with pneumatic tires, it is impractical to attempt such an arrangement. Instead of this arrangement, a radio receiver mounted on the motor vehicle is usually grounded to the vehicle chassis. However, the chassis of a motor vehicle is usually made up from a number of metallic and nonmetallic parts, some forming good electrical conductors and some forming very poor conductors that are not connected together with the idea of providing a path for electrical currents. For this reason, the metallic parts adjacent to the antenna, which may be mounted in the roof of a car, over the hood or under the chassis, are oftentimes loosely connected to the metallic parts adjacent to the radio receivers per se where it it would be convenient to ground the receiver.

In order that the radio receiver may be grounded to the metallic parts adjacent to the antenna, a lead has been extended from the radio receiver to a point near the point of juncture between the antenna per se, and the lead connecting the antenna to the radio receiver.

Another function of the return ground lead is to provide a disturbing signal pick up which will counterbalance the disturbing signals picked up by the lead in.

An object of this invention is toprovide an antenna that will reduce the amount of disturbances caused by the ignition system of the motor vehicle. This has been accomplished by grounding the antenna circuit near the point where the lead from the antenna to the radio receiver is joined to the antenna.

Another object of this invention is to provide a counter-poise that is adjacent to the antenna. This has been accomplished by grounding the radio receiver at a point near the juncture where the lead in is attached to the signal receiving portion.

Another object is to eliminate the variable efiective constants of the antenna circuit caused by loose connections between the metallic parts. This has been accomplished by grounding the antenna circuit to the metallic parts of the motor vehicle adjacent to the receiving portion.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 discloses a preferred modification of an antenna mounted in the roof of a motor vehicle and the antenna circuitmounted near the top of the vehicle.

Figs. 2 and 3 disclose another modification similar to Fig. 1.

In the drawing the reference character 10 indicates the roof of a car provided with the receiving portion 12 of an antenna circuit including the lead in 14, suitable coupling apparatus 16 the antenna circuit signal receiving portion has been mounted on the top of the motor vehicle, it may be mounted any other convenient place within the purview of this invention providing the ground lead 18 is grounded at a point 20 on the metallic parts adjacent to the signal receiving portion, 12 so that the relative potential between the signal receiving portion 12 and the metallic part nearby will not be altered by loose connections between the metallic parts.

In the modification disclosed in Fig. 2, all parts are identical to the disclosure in Fig. 1 excepting the lead 14 passes through a tubular metallic member 28 which serves the functions of a ground and of a shield.

The modification disclosed in Fig. 3, is identical to the modification disclosed in Fig. 2 excepting instead of the tubular metallic member 28 either a wound or woven ground 38 partially enclosing the lead 14 has been used.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An antenna circuit for a radio receiver mounted on a motor vehicle or the like containing a framework of conducting material. said antenna circuit including a signal receiving portion, a lead in, a reactance unit and a ground lead, said ground lead extending substantially parallel to the lead in so that the circuit is grounded to said conducting irame adjacent to the juncture of the receiving portion and the lead in.

2. An antenna circuit for a radio receiver mounted on a motor vehicle or the like, said antenna circuit including a signal receiving porlead joined to said signal receiving portion, a tion, a coupling unit and a ground lead grounded adjacent to the juncture of the first mentioned lead and the signal receiving portion, said ground lead including a conducting member partially enclosing the first mentioned lead so as to shield this lead from electrical disturbances.

3. An antenna circuit for a radio receiver mounted on a motor vehicle or the like, said antenna circuit including a signal receiving portion, a lead connecting the receiving portion to the radio receiver and a ground lead extending from the radio receiver to a metallic counterpoise adjacent to the receiving portion, said ground lead including a tubular member enclosing a portion of said first lead so as to form a shield protecting said lead from disturbing radiations.

LAURENCE M. PERKINS. 

